Attachments not opening on New Outlook desktop app

Question

Attachments not opening on New Outlook desktop app

Joshua O 10

For about a week now, I have been unable to open attachments on my New Outlook desktop app. When I click a button to open an attachment, an error message comes up saying "Can't open the file Please restart Outlook and try opening the file again." I have been on multiple computers, all of which have been restarted multiple times since this error started.

I found that people have been having this issue for a while based on posts here, but I was unable to find a satisfactory resolution. Any help would be appreciated, as this is starting to significantly impact various job functions.

Jeff Montague 5 Reputation points

2026-10-29T16:42:21.6733333+00:00

Hi Joshua. FYI Below:

Issue ID: EX1528992 Affected services: Exchange Online Status: Service degradation Issue type: Advisory Start time: Oct 28, 2026, 9:24 AM PDT More info Impacted users may be presented with an error that the file can't be opened and to restart Outlook to try again; however, the "Open" option is no longer available after encountering the error. Users can select "Save as" to download the file and then open the attachment to bypass the impact. Scope of impact This issue affects new Outlook desktop users who have upgraded to Edge version 156. This section may be updated as our investigation continues. Root cause A recent update to Edge Version 156 unintentionally enabled an unnecessary configuration change and is resulting in impact. Current status Oct 28, 2026, 6:05 PM PDT We’ve determined that a recent update to Edge Version 156 unintentionally enabled an unnecessary configuration, resulting in impact. We’ve developed and deployed a targeted fix to disable this configuration, which may take up to 12 hours to propagate across our service infrastructure. We’ll use service telemetry to confirm the fix has been applied across the infrastructure. Once confirmed, users will need to close and reopen New Outlook for the change to take effect and resolve the issue.

2 answers

Your answer

Jeff Montague 5 Reputation points

2026-10-29T16:42:21.6733333+00:00

Hi Joshua. FYI Below:

Issue ID: EX1528992 Affected services: Exchange Online Status: Service degradation Issue type: Advisory Start time: Oct 28, 2026, 9:24 AM PDT More info Impacted users may be presented with an error that the file can't be opened and to restart Outlook to try again; however, the "Open" option is no longer available after encountering the error. Users can select "Save as" to download the file and then open the attachment to bypass the impact. Scope of impact This issue affects new Outlook desktop users who have upgraded to Edge version 156. This section may be updated as our investigation continues. Root cause A recent update to Edge Version 156 unintentionally enabled an unnecessary configuration change and is resulting in impact. Current status Oct 28, 2026, 6:05 PM PDT We’ve determined that a recent update to Edge Version 156 unintentionally enabled an unnecessary configuration, resulting in impact. We’ve developed and deployed a targeted fix to disable this configuration, which may take up to 12 hours to propagate across our service infrastructure. We’ll use service telemetry to confirm the fix has been applied across the infrastructure. Once confirmed, users will need to close and reopen New Outlook for the change to take effect and resolve the issue.

Answer 1

Hi Joshua,

Thank you for reaching out.

Since the issue occurs on multiple computers, it may be connected to the mailbox, the New Outlook app, or an organization-level security policy rather than one specific device. Please try the following steps:

Test the attachment in Outlook on the web

Sign in to https://outlook.office.com and try to open the same attachment.
If it opens successfully, you can use Outlook on the web as a temporary workaround while troubleshooting New Outlook.
If it does not open, please note whether the same error appears.

Download the attachment

Select the menu next to the attachment, choose Download or Save as, and then try opening the saved file from File Explorer.

Please also check whether the problem affects every attachment or only specific file types, such as PDF, Word, or Excel files. New Outlook for Windows supports saving attachments locally through the attachment menu.

Repair or reset the application

Close Outlook.
Open Settings > Apps > Installed apps.
Find Outlook.
Select the three-dot menu, and then select Advanced options.
Select Repair and test Outlook again.

User's image

If the problem continues, return to the same screen and select Reset.

Contact your IT administrator

If the issue continues, especially if attachments also fail in Outlook on the web, please contact your Microsoft 365 administrator. Ask them to check:

Whether attachment security, Microsoft Defender, Conditional Access, or sensitivity-label policies are affecting your account.
Whether another user in the organization can open the same attachment.

I hope your issue gets resolved soon. Any updates would be greatly appreciated.

Joshua O 10 Reputation points

2026-10-27T20:47:47.75+00:00

Thank you for your recommendations! Unfortunately, the attachments are unable to open on the web version as well (an open button does not even appear on the web), and the issue persists even after repairing and resetting.
Jay1 Tran 1,910 Reputation points Independent Advisor

2026-10-28T19:09:54.49+00:00

Hi Joshua,

Thank you for your response.

If the issue persists even in Outlook on the web, I recommend reaching out to your IT admin and ask them to open a support ticket with Microsoft via the admin center. A technical support engineer can then initiate a remote session, review backend settings, and run diagnostics. If needed, they can escalate the case to specialized engineering teams who are well-equipped to perform advanced troubleshooting and provide targeted solutions.

For guidance on how to request support in the admin center, please refer to: Get support - Microsoft 365 admin.   

Thank you again for your time and cooperation during this process. Wishing you a great day ahead.

Answer 2

Create the missing local Attachments folder under New Outlook’s OLK data directory, which directly matches the reported “Can’t open the file—Please restart Outlook” attachment error.

Create the OLK Attachments folder

Since restarting on several computers has not helped, do this on one affected computer first:

Close New Outlook.
Press Windows key + R.

Enter:

   %userprofile%\AppData\Local\Microsoft\OLK

Select OK.
Look for a folder named Attachments.
If it is missing, right-click an empty area, select New > Folder, and name it exactly:
```
   Attachments
```
Reopen New Outlook and test a known attachment.

A matching New Outlook case found that attachment downloads failed when this local folder was absent; creating it resolved the problem.^1^

If the folder already exists, do not delete the entire OLK directory; move to the checks below.

Determine whether the failure is client-side

Open the same message in Outlook on the web and test the same attachment:

It opens on the web: The mailbox and attachment are accessible, so continue with the New Outlook app repair below.
It also fails on the web: Skip local app repair and involve your Microsoft 365 administrator, because the problem is not confined to that computer’s New Outlook installation.

As a temporary workaround, the attachment menu in New Outlook or Outlook on the web supports Download and Save to OneDrive.^2^

Repair or reset New Outlook

Only use this branch if attachments work in Outlook on the web but the Attachments folder fix did not resolve the desktop app.

On Windows 11:

Open Start > Settings > Apps > Installed apps.
Find Outlook (new).
Select the three-dot menu > Advanced options.
Select Repair, then test Outlook.
If Repair does not work, return to the same page and select Reset.

Reset clears the app’s local state and requires you to set up or sign in to the app again. Windows documents Repair as the non-destructive first option and Reset as the next step when Repair fails.^3^

Business-admin checks

If the error occurs in Outlook on the web too, or affects multiple users:

A Microsoft 365 administrator should open Microsoft 365 admin center > Health > Service health.
Check Exchange Online and Microsoft 365 advisories, including both active issues and recent issue history.^4^
If no relevant incident appears, open a Microsoft 365 support request and include:
- The exact error text.
- Whether all attachment types and old/new messages are affected.
- Whether opening, downloading, and saving to OneDrive fail.
- Results from New Outlook and Outlook on the web.
- Confirmation that it reproduces on multiple computers.
- Whether the OLK\Attachments folder existed and whether creating it changed the result.

The public New Outlook known-issues page does not list this exact attachment-opening error, so an unresolved cross-client or multi-user failure should be submitted as a tenant-specific support case rather than treated as a confirmed public incident.^5^

References